I like that it's easy to use, has great documentation for new users, and integrates with most of my favorite apps. It can be difficult to get started if you're not familiar with backend development. There are many different ways to accomplish similar tasks which makes things confusing at first. You have to learn how to do everything yourself or pay someone else to help you. If you want an all in one solution then this is probably what you need. We needed something simple to integrate into our app so we could send push notifications from our server without having to write code ourselves.